Recent Colds Could Lower Risk of Severe COVID-19
Rhinovirus infections are linked to reduced COVID-19 risk and lower viral loads, especially in children.
Prior rhinovirus infections, a common cause of the cold, are associated with a reduced risk of developing COVID-19 and with lower SARS-CoV-2 viral loads, according to findings published in The Journal of Infectious Diseases.
The study was led by researchers at National Jewish Health and involved data from the Human Epidemiology and Response to SARS-CoV-2 (HEROS) cohort, a US-based surveillance study conducted between May 2020 and February 2021. The findings may help explain why children, despite being more vulnerable to many respiratory viruses, tend to experience milder outcomes from SARS-CoV-2 infections.
Rhinovirus
A common virus that causes upper respiratory infections such as the cold.SARS-CoV-2
Severe acute respiratory syndrome coronavirus 2, the virus responsible for causing COVID-19.
Viral load
The amount of virus present in a person's body, typically measured using molecular testing methods.Assessing viral interactions in the airway
The researchers analyzed 10,493 nasal swab samples from 1,156 participants, including both children and adults. These samples were tested for 21 respiratory pathogens. Additionally, RNA sequencing was carried out on 147 swabs collected before SARS-CoV-2 infection and 391 swabs collected before and during rhinovirus infections.
RNA sequencing
A laboratory technique used to analyze the expression of genes by examining the RNA in a sample.The team evaluated the potential relationships between recent rhinovirus infections, COVID-19 risk, antiviral gene activity in the airway and participant age. Their findings showed that recent rhinovirus infections were linked to lower susceptibility to SARS-CoV-2.
Reduced COVID-19 risk and viral load
Participants who had tested positive for rhinovirus within the prior 30 days were at a 48% lower risk of contracting COVID-19 than those without recent rhinovirus infection. Among individuals who developed COVID-19, those with recent rhinovirus infections had viral loads that were 9.6 times lower than those without such prior infections.
The authors noted that rhinovirus infections triggered elevated expression of antiviral genes in the nasal airway. Of 57 genes linked to reduced SARS-CoV-2 viral load, 24 were classified as antiviral defense genes. Rhinovirus was associated with the activation of 22 of these genes.
Children were more likely than adults to express higher levels of these antiviral gene signatures and were 2.2 times more likely to contract rhinovirus.
Recent symptomatic infections offer the greatest protection
Sensitivity analyses suggested that recent and symptomatic rhinovirus infections were more protective than asymptomatic or earlier infections. This temporal and symptomatic relationship may be relevant in understanding variations in susceptibility to COVID-19.
According to the researchers, frequent rhinovirus exposure could reinforce antiviral gene activity in the airway, contributing to reduced risk of severe outcomes from SARS-CoV-2. This gene-driven protective mechanism may help explain why children generally experience milder COVID-19 symptoms compared to adults.
Reference: Moore CM, Secor EA, Everman JL, et al. The common cold is associated with protection from SARS-CoV-2 infections. J Infect Dise. 2025:jiaf374. doi: 10.1093/infdis/jiaf374
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